反应详情

Crude (3E)-3-(ethoxycarbonyl)-4-[1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazol-4-yl]but-3-enoic acid (45 g) was mixed with acetic anhydride (500 mL) and NaOAc (12 g, 0.146 mol). The reaction mixture was heated at reflux over a period of 5 hours and evaporated. The residue was alkalized to pH 8-9 with aqueous Na2CO3. The product was extracted with EtOAc (5×50 mL). The combined extracts were dried and evaporated. The residue was purified by chromatography (EtOAc/hexane, 1:4) to provide ethyl 7-(acetyloxy)-1-(tetrahydro-2H-pyran-2-yl)-1H-indazole-5-carboxylate (13 g, 25%).

1. temperatureThe reaction mixture was heated
2. temperatureat reflux over a period of 5 hours
3. customevaporated
4. extractionThe product was extracted with EtOAc (5×50 mL)
5. customThe combined extracts were dried
6. customevaporated
7. customThe residue was purified by chromatography (EtOAc/hexane, 1:4)